The circular stocking knitting machines, whether they are single feed or multiple feed, are usually provided with a device for cutting the threads, which consists of a circular saw having teeth facing towards the outside and of one or more knives having the function of a counterblade. The saw is fixed and rotates with the plate, while the knife remains stationary. Therefore, any tooth of the saw can, with its front part, intercept the thread that comes close to it as a result of an appropriate movement of the relative thread guide, and interacting with the fixed knife, cuts the thread.
Normally, the length of the tail of the thread that remains when cut is that from the outlet point of the thread from the needles to the cutting of the tooth of the saw, which coincides with the front part of the tooth which grips the thread and which interacts with the knife for the cutting. However, the distance between the needles and the saw teeth is often limited, and the tail of the cut threads can be too short. In some knitting operations, especially in the presence of elastic threads, such a tail of the threads, if it is too short after the cutting, can become unthreaded from the knitting, and from the reverse side to the right side of the manufactured article.